Monthly Archives: July 2022

How droughts can even impact your air

It’s been an unusual year.  In the southeast US, temperatures have been above normal with extended periods of no rain.  In the west, Lake Mead and Lake Powell have lowered by nearly 75% of where lake levels once were as the country's two largest reservoirs.  The Colorado River, which supplies these lakes, is used by seven surrounding states, and for decades annually the region was taking out about 1 million acre-feet of water more than the river was providing (Los Angeles Times).  Much of the country is in drought, and the Southwest is experiencing a megadrought–one it has not seen in 1,200 years. 

What is drought?  Drought arises only after a prolonged (>week) period of precipitation shortage that causes soil to dry up, and these period(s) may reoccur monthly.  Further, the prominent feature of drought is water deficit in both the atmosphere and the land component (e.g., soil and vegetation), resulting from the combination of precipitation shortage and increasing evapotranspirative water loss driven in part by high temperatures.   (2017 study).  When drought hits home, it’s more than water restrictions on your lawn. Here are some of the effects: 

• Droughts increase ozone and PM2.5. A study released in 2017 examined air quality during 4 severe droughts and found that elevated ozone and PM2.5 are attributed to the combined effects of drought on deposition, natural emissions (wildfires, biogenic volatile organic compounds (BVOCs), and dust), and chemistry. In our post “It’s not the heat, it’s the humidity air pollution”,we noted the correlation between extreme heat and ozone.  Here are some other facts brought forth by the 2017 study: 

• Meteorological conditions/extremes likely to co-occur with drought that are also associated with higher pollution levels. For example, high ozone is more likely to occur with high temperature and low RH (2016 study; 2017 study, 2016 study 2)

• more frequent stagnation and heat waves could explain up to 40 % of the ozone and PM2.5 enhancements during drought

• Since anthropogenic sources of ozone and PM2.5 have decreased significantly since 1990, the ozone and PM2.5 enhancements during drought are largely responses of natural processes from the land biosphere and abnormal atmospheric conditions. 

• Droughts affect plants and their interaction with atmospheric ozone in complicated ways.  Some plants take in ground-level ozone, while other plants emit isoprene, a VOC that reacts with other atmospheric chemicals to create ozone. (Scientific American).  While studying the 2011-2015 drought in California, scientists found that: 

• Dry conditions caused the plants to restrict water loss by closing their stomata (pores), which means taking in less ozone (ozone levels rose). Absorption did drop by about 15% during the most severe years of the drought.

• Plants and trees were able to sustain isoprene production during the first three years by drawing on their carbon stores; isoprene helps them against heat stress. 

• After 4 years, isoprene production dropped, and so did ozone (by 20%).  

• Drying lakebeds (like the Great Salt Lake in Utah) expose people to toxic elements like arsenic when dust storms pick up lake bed dust, which are residuals of pesticides and agricultural chemicals that migrated into the lake over many decades.. (New York Times)  Another dried lake that causes air quality problems is Owens Lake in California, which is the country’s largest source of PM10 (geochange.er.gov).

• Droughts can increase transmission of soil and dust-transmitted diseases like Valley Fever, which is coccidiodomycosis (Cocci for short).  Dust that is liberated from the soil during digging activities or dry, windy conditions can carry the fungus, which workers or residents can breathe in.  It causes symptoms like fever, cough and tiredness, but can occasionally be serious or deadly.

• Trees and plants weakened by drought are more vulnerable to pests and disease, which can kill large numbers of them. Plants that succumb to drought and die cause several problems:

• they turn from absorbing ozone and CO2 to emitting carbon via CO2.  

• Dead plants and trees increase the risk of wildfires.

• Droughts impact electric power generation systems (the Grid)in the following ways (americanscientist.org):

• Hydropower is reduced because of low stream flow

• Demand for electricity increases because increased cooling is needed in homes and offices 

• Fossil-fuel plants (coal, natural gas) must increase production of electricity.

• This means that air pollution increases during drought due to our electric power generation system. IF changes can be made to shift to “cleaner” generators (ie. natural gas instead of coal) during drought, it is generally better for air quality. 

In all, drought is a serious, complicated blight on both the land and the air, which we at HypoAir have felt for some time because California has been in long-term drought.  Finding ways to reduce water and energy consumption helps everyone, so don’t wait until regulations forces change–here’s a list of ways you can help your community and family before and during drought.  However, it’s the unseen increases in ozone, PM2.5, fungus and other forms of air pollution for which the public generally doesn’t prepare.  Here are some ways you can be smarter about air pollution from drought:

• Continue to work on air sealing your home

• Have extra MERV 13 furnace filters, air purifier filters, and filter media on hand so that you can change these more frequently

• Have N95 respirators on hand for the immune-impaired who need to go outside 

• Be cautious about excavation and construction work in areas where Valley Fever is a risk (wear an N95 mask if necessary)

What’s the difference between EMMA and ERMI?

Maybe EMMA and ERMI sound like children’s story characters, but no, we’re talking about mold testing!   RealTime Laboratories was founded in Texas in 2005 by two doctors who had been researching and collaborating since their meeting in medical school.  Dr. Bolton is a board-certified anesthesiologist and was a doctor with the U.S. Navy for 12 years, as well as practicing privately and with the U.S. Department of Veterans’ Affairs.  He investigated the circumstances of his friend’s mother’s sudden death, whose heart stopped although she was in relatively good health.  The woman’s house was full of mold.  Dr. Bolton’s wife also suffered from sinus and ear problems, most likely from the gym where she worked out (nadallas.com) At RealTime Laboratories, Dr. Bolton and Dr. Hooper developed proprietary testing for the 16 most common, dangerous mycotoxins in patients’ bodies, homes and pets, so that they could recover their homes and lives from these poisons.  EMMA (Environmental Mold and Mycotoxin Assessment) is one of these tests, and it tests for 10 of the most toxigenic molds (including “Black Mold” or Stachybotrys) as well as the presence of 16 of the most dangerous mycotoxins produced by those 10 molds, using provided swab and gauze or a sample of your HVAC filter. (realtimelab.com)

In contrast, ERMI (Environmental Readiness Moldiness Test) was developed by the EPA as a research tool, to investigate the relative moldiness of a home.  ERMI uses the analysis of settled dust in homes and buildings to determine the concentrations of the DNA of the different species of molds.  (survivingmold.com)  In other words, ERMI gives a sense of the concentration of various molds, but does not test for the poisonous mycotoxins they emit. ERMI was developed as a research tool only, and although ERMI testing is widely available by independent labs, it has not been validated for routine public use in homes, schools or other buildings.  It was criticized by the EPA’s own Office of Inpector General in a report titled, “Public May Be Making Indoor Mold Cleanup Decisions Based on EPA Tool Developed Only for Research Applications.”  Some of the shortfalls of ERMI collection practices and analysis are listed in this report. 

Here is a summary of the differences between EMMA and ERMI (source: presentation by Dr. Matt Pratt-Hyatt):

Realtime Laboratories is certified under Clinical Laboratory Improvement Amendments of 1988 (CLIA) and College of American Pathologists (CAP) to perform EMMA testing, which most importantly focuses on the molds AND the mycotoxins they produce.  The company has produced a table of which mycotoxins are associated with which mold, and the symptoms and illnesses caused by them.  Here is a portion of the table:

Mycotoxin testing in the body is what may be foremost to patients.  This lab offers urine sample testing of those same 16 mycotoxins using ELISA-based testing, which stands for enzyme-linked immunoassay. It is a commonly used laboratory test to detect antibodies in the blood. (medlineplus.gov).  (Inclusive in the mycotoxin test, RealTime Labs was granted a patent for its macrocyclic trichothecene test (tricothecenes can be produced by the molds Fusarium, Stachybotrys, Tricothecium and Myrothecium)).  Also, RealTime Labs offers a MycoDART-PCR test of the blood (must be ordered by a doctor) to determine if the patient has been colonized by mold.  According to Dr. Matt Pratt-Hyatt, 1 in 3 mold illness patients is colonized with mold.   If detectable levels of mycotoxins are found:

• In the body: the patient can choose to start treatment with a doctor in their area (list on the website).  Treatment and monitoring continues until mycotoxins are below detectable limits in the tests.  

• In the home: the patient can contact environmental remediation services to pinpoint the source (the test does not pinpoint the source) and remove mold from their home.  

Recovery from mold exposure and mold illness really needs to have this dual approach, because if the patient is treated without remediation of the home, then continued exposure will not allow recovery!  Remediation of the home is great, but it could take much longer for the patient to recover if their natural defenses, like glutathione, remain depleted.  Want to know whether you or your home have been “sickened” by mold?  Get tested! 

• For the patient: 

• Mycotoxin testing by RealTime Labs: $399, by urine sample

• For the home:

• EMMA testing by RealTime Labs: $399 by dust swabs or air filter sample

• Got Mold? Testing, $149-249 for 1-3 rooms 

Fiberglass: the air quality problem you didn’t consider

With extreme weather issues such as storms and fires in the news, we can become very focused on mold from water damage and particulate matter (PM) from air pollution like smoke, but another problem has been silently causing lung and whole-body issues for decades: fiberglass insulation.

Fiberglass insulation, also known as glass wool, was accidentally invented in the 1930’s and patented in 1938 as Fiberglas.  It became a popular insulation for building and comes in batts, with a paper or plastic backing, or is available in loose form in bags, that can be blown into place.  Now fiberglass is used in: 

• Appliances like dishwashers, refrigerators, ovens, exhaust fans, clothes dryers
• Kerosene heaters and wood-burning stoves
• roof shingles
• Beds (also known as a silica sock)
• Cigarette filters
• HEPA and HVAC filters
• Light fixtures
• Carpets
• Packing tape
• And even some brands of toothpaste!

Children may be especially vulnerable to potential effects from fiberglass particle inhalation. “We’ve seen a substantial increase in air quality concerns from homeowners with young children experiencing chronic cough and eye irritation,” says Jeffrey Bradley, president of IndoorDoctor LLC. Bradley says fiberglass is often the culprit. (iqair.com)

Like most materials, fiberglass insulation degrades over time, and water speeds up the degradation process.  Therefore, although blown-in insulation is a popular choice for insulating attics and walls, leaving fiberglass exposed to humid air can cause the fibers to break and become airborne.  Typically, most manufacturers warn about wearing masks if you manually “disturb” the insulation by pushing past it or cutting into it.  However, loose fiberglass that is exposed to air currents can pick up these small fibers without manual disturbance, resulting in unhealthy PM2.5 levels in homes where it gets entrained into the air conditioning system.  

One woman has detailed her family’s project to remove all the fiberglass from their house after it was determined that fiberglass dust was making her sick.  Fiberglassawareness.com is a very useful website with many photos of where fiberglass is used in homes, and even cars and other buildings where you may not suspect it.  That pink (or yellow or white or green) stuff that you thought remained in the attic, doesn’t always stay where it belongs!  Wherever you can see exposed fiberglass, it may be emitting small particles into the air.  That means if it is peeking out of the ends of wrapped ducts, or falling (sometimes imperceptibly) out of can light fixtures, or being sucked into your AC system through small leaks in the ducts, it is in the air you breathe and can cause a myriad of health issues.  This page details a long list of fiberglass-exposure symptoms which overlap with mold-exposure symptoms, fibromyalgia symptoms, and auto-immune disorder symptoms, so the main culprit can be hard to diagnose.  In addition, many fiberglass insulation products use:

• Phenol formaldehyde to bind the fiberglass fibers together (iqair.com), and the off-gassing of formaldehyde can cause similar symptoms. Formaldehyde is a carcinogen and exposure to fiberglass insulation formaldehyde causes brain cancer. According to John D. Spengler et.al., in the "Indoor Air Quality Handbook," residents of mobile homes who are exposed to fiberglass insulation are at increased risk of brain cancer. 
• Styrene or Vinyl-Benzene is found in fiberglass insulation, and because benzene is used in many home other consumer products like water bottles, convenience food trays and wrappers, and feminine products, it contributes to a thick low-lying VOC cloud in some homes. According to Teresa Holler in the book "Holler for Your Health," styrene is toxic to the nervous system and exposure to styrene in fiberglass insulation causes behavioral changes, concentration problems, depression, tiredness, headaches, memory problems and weakness.  According to Andre E. Baert in the book "Biomedical and Health Research," long-term exposure to styrene in fiberglass insulation causes brain tumors and cancer. (ehow.com)
• Methyl-ethyl-ketone (MEK) is used as a binder in some fiberglass.  Nick H. Proctor et.al., in the book "Proctor and Hughes' Chemical Hazards of the Workplace," list methyl ethyl ketone as a neurotoxin and exposure to MEK in fiberglass insulation as a cause for dizziness, nausea, headaches, depression and unconsciousness. (ehow.com)

According to the California Department of Public Health, frequent exposure to fiberglass insulation causes permanent changes in the central nervous system, the symptoms of which include personality changes, poor coordination, fatigue and poor concentration.(ehow.com)

How do you get rid of fiberglass in the air?  In some cases “encapsulation” can be an answer, which means that you can add a layer of protection over it.  We should never see exposed fiberglass (the brown paper side is supposed to be installed on the “warm” side, which in southern climates leaves the fiberglass exposed to the inside of the attic).  This real estate inspector wrote an article on encapsulation from the point of view that fiberglass is a poor air barrier and therefore should have a proper air barrier on both sides.  However, he notes at the end that a homeowner should not try to encapsulate any fiberglass himself, because of the risk of causing mold if moisture cannot escape.  

Here’s how you can minimize your exposure to fiberglass: 

• Repair damaged sections of fiberglass insulation with proper foil duct tape.
• If you have blown-in fiberglass in your attic or walls, seal all penetrations such as ceiling fixtures, wire and plumbing penetrations, light switches, and cracks in drywall
• Check the internal condition of any “duct board” ducts or ducts internally insulated with fiberglass.  Unfortunately these degrade over time and cause the fibers to become entrained in the air.
• If your health issues have not resolved, consider removing some or all of the fiberglass that could be causing them. 
• Replace fiberglass insulation with ducts that are insulated with air bubble wrap, and walls and ceiling insulation with spray foam or cellulose insulation (however, be aware that cellulose insulation is treated with fire retardants to make it safe, which can cause other health issues to those who are sensitive). (nachi.org)

If you know or suspect that your health problems are being caused by fiberglass or VOCs that come from the fiberglass, keep a journal of how you feel during the day at different times, including where you are, what you are doing,  if the building’s HVAC is running, what you are wearing, eating, working with, etc.  It’s possible that you can find the link by putting the pieces together from your experiences, and from others’ experiences.  Research sites of others with environmental and chemical sensitivities, such as Fiberglassawareness.com, mychemicalfreehouse.net, and nontoxicforhealth.com (the latter two have a lot of scientific research on them), and don’t give up! 

What kind of air conditioner do you have?

An air conditioning system is certainly not the most interesting equipment that you choose for your home, or that comes with an existing home you buy.  It either works well, or it doesn’t, right?  Unfortunately it’s the ones that don’t work well that get noticed!  Depending on the size of home, configuration and budget, there are about 7 different types that may be used.  Here’s how to tell what kind of unit you have, and what kind you may want to upgrade to in the future!

Before talking about all the different types, however, let’s go over the basic parts of an air conditioner by looking at one of the most compact and common versions, a window air conditioner. 

(diagram source: studentlesson.com)

The components of a window air conditioner can be found in most other systems.  To start, note that the outside air and the inside air don’t mix.  Indoor air stays inside and outdoor air stays outside; it’s the refrigerant in the coils that goes back and forth, transferring heat from indoor air to the outside air.  Let’s start with warm indoor air.  In this diagram, it’s sucked into the unit from the right (“Indoor Air” red line), via a squirrel-cage blower (circular cage), and blown over the cooling coils (blue line going back and forth), making the air cool.  The air is blown out the front of the unit and voila!  The room becomes cooler.  What happened to the heat from the air?  Here it’s useful to show another diagram, which is of the refrigerant system only.  

(diagram source: swtc.edu)

Once you understand this inside/outside, low-pressure/high-pressure system, you will be able to understand most of the common refrigeration systems!  The heat of the inside air was absorbed by the refrigerant in the cooling coils (see left side of diagram).  The cooling coils are also called the evaporator, because inside the cooling coils, the refrigerant changes from a liquid to a gas (evaporates) with the addition of the heat of the inside air. Once the refrigerant passes all the way through the evaporator, it is drawn outside by the compressor, which changes it from a warm gas to an even hotter gas.  The hot gas will then pass through the condenser, which is another set of coils over which a fan blows outside air.  When heat is drawn from the gas, it turns into a liquid again (upper right side of the diagram).  Before passing to the evaporator again, it must flow through the expansion valve, which is a very important part of the air conditioner.  The expansion valve gets a signal from the temperature sensing bulb (first diagram), and only lets a small portion of the hot pressurized gas into the evaporator as needed, creating a low pressure area on the cooling side.  Then we have completed the cooling cycle, and the refrigerant makes another loop while the fans serve to transfer heat to the air on each side of the window.  

Central Air Conditioning uses all of these basic components, serves multiple rooms in a home, and can be categorized into two types: Split and Package.  The main difference between these two is the location of the evaporator.   In addition, central air conditioning can be used for heating if it uses a heat pump.  (see the section at the end to learn a little more about heat pumps).

• Package units are very much like window air conditioners because the compressor, condenser and evaporator are all in one outside unit (B below).  Sometimes you can recognize a package unit if there is a large metal duct running from the unit into the home (sometimes, like in the diagram, the duct is hidden behind the unit).  Commercial rooftop units (A below) are often package units.  The advantage of these is that all of the noise and heat of the air handler is outside and the unit comes ready to be attached to the ductwork. 

(source diagram: refrigeratordiagrams.com)

• Split units have the compressor and condenser located outside (unlabeled unit to the left below), while the evaporator/air handler is located inside.  Normally the evaporator/air handler is located in a closet, garage, attic or crawl space.  From this point the cooled air is distributed throughout the home via supply ductwork.  

Source diagram: thisoldhouse.com

Mini-Split systems are a takeoff of “central split systems” in that the evaporator is located inside, but air distribution ducts are eliminated.  For this reason, mini-splits are also called ductless systems, and because air ducts can be a source of energy loss, they are more efficient.  They used to supply refrigerant to only 1 evaporator (1 room), but modern units (Carrier for example) can supply refrigerant to up to 9 rooms. (thisoldhouse.com)  Instead of circulating cooled air through ducts, the refrigerant is sent into the home to small concealed or wall-, ceiling- or floor-mounted evaporator/fan systems.  It is a good solution for remodels and additions: instead of adding more ductwork or replacing a huge central unit that may be too small to serve the addition, add a mini-split to serve the new area.  Mini-splits can also be heat pumps to heat the area during winter (see section at end on heat pumps).

Mini-Split diagram source: armstrongair.com

Finally, portable air conditioners (PACs) are just that: you can move them from room to room easily, and even store them in a closet when not in use, because they are usually on casters.  Portable air conditioners are a type of “package” unit because the evaporator, compressor and condenser are all located in one unit, but it is inside.  In order to extract and remove all that heat, there are one or two hoses coming out of the unit, which must be run through a window or other opening.  If the unit only has one hose, the unit is sucking air from the room it’s cooling, running it over the condenser, and expelling it outside.  This creates a slight negative pressure in the room, in turn pulling un-conditioned air from any cracks and crevices in the room’s envelope.  Dual-hose units pull in outside air to cool the condenser, pushing it back out via the other hose, which is more efficient but can be a little more expensive and possibly more noisy.  In general, PACs are less efficient than window air conditioners, but their convenience to use (especially in climates where they are only needed several days of the year) makes them popular.  

source: whirlpool.com

Heat pumps: We mentioned that central air and mini-splits have the ability to heat as well as cool.  By reversing the flow of refrigerant, heat can be extracted from the air outside and carried inside.  These work well in mild climates that have temperate winters that don’t go much below 40 deg F.  

Source diagram: thisoldhouse.com

Purification that works with your air conditioner

What types of purifiers do we recommend with these different types of air conditioners?  We’re glad you asked!  Here is a table explaining what’s available:

Of course, Air Angels and Germ Defenders are great portable solutions that you can use in any room even if you are also using a whole-home purifier, and HEPA units are also useful in high-dust or allergy-prone areas.  The Cleanroom WindPRO 650 is a great option for a large open space, with its electrostatic filter (can be washed) and carbon filtration against VOCs and odors. 

HVAC Filter Monitors–Can they really optimize your filter life?

Most people are NOT like my mother, including me!  She always does the laundry on Monday, changes the smoke alarm batteries on the Daylight Savings dates, and changes the HVAC filters on the same day every month.  These are predictable, safe things to do, and are probably one of the reasons she gets great insurance rates and her home looks nice whenever you drop in.  Younger generations like myself like to “optimize” but sometimes that gets us in trouble: in my case someone else has claimed the laundry room with their clothes for several hours exactly when I run out of clean clothes, smoke alarms start chirping in the middle of the night when I have guests, and on the day I remember to check the AC filters, they are very dirty and I have no replacements on hand.  I do well with alarms, however, as long as they think like I do (optimize) and  I have some “margin” to rectify the situation.  

What do I mean by “optimizing”?  The problem with changing your AC filter on the same day every month is that not every month is the same, meaning that there may be some filter life remaining at the end of the month.  April in the Southeast US can be very pleasant with very little “air conditioning” required, while July is–you guessed it–like a swamp.  Of course the AC will be running 31 days in July, but not so much in April.  I don’t want to throw out a filter that looks almost new, just to be on schedule, but…how will I know when it’s full of dust and contaminants?  That’s the question.  “Optimizing” to me means getting the most out of whatever I use, whether its the AC filter or the toothpaste tube (flatten that sucker!).  The traditional “Filter” light and reset button on my thermostat that will cause the light to come on 30 days later are NOT optimizing the filter.  That’s just a blind schedule.  So, let’s talk about how newer HVAC filter monitors work!

Temperature: Rittal makes many products, including air conditioners for residential and industrial use.  They have a filter monitor that uses the change in temperature over the air coil to judge filter life.  When the change in temperature (delta T) becomes too high, this indicates a clogged filter.  I haven’t found any standalone residential products that use delta T to monitor filter life, however.

Light:  HVAC filters are porous, obviously.  They let air pass through and they also let light pass through.  An optical monitor can take a “baseline” measurement of how much light passes through when the filter is new and clean, and when the light becomes too occluded, it will notify you because this means the filter is dirty.  Simple concept!   Filter Pulse HVAC Indoor Air Filter Monitor (starts at $66) is one such product.  It can be ordered with brackets to fit up to 5” filters, and the power source is either battery or 24V AC power.   This technology allows it to be used even with new variable-speed blowers, because the variable pressures in these systems will not affect the light sensing technology. 

Pressure drop:  This is the traditional method of determining when your AC filter is dirty, because as dust and contaminants are deposited on your filter, the little “holes” that allow air to pass through become plugged, and the pressure will be higher on the inlet of the filter and lower at the outlet of the filter.  The pressure differential between inlet and outlet will become greater.  Some HVAC techs will recommend that when the dirty filter pressure drop is close to double of that of the initial/clean filter pressure drop, it’s time to change the filter (John Semmelhack, ComfortSquad.us).  However, pressure drop monitors will not work with newer variable-speed blowers, because lowering the speed of the blower (which automatically happens) will decrease the pressure differential.  Thus it may give a false “clean” reading when operating with a variable speed blower.

Here are some low and high-tech indicators of pressure drop:

• Simple analog gauge: This gauge can be set with a clean filter and shows the pressure increase until the needle lands in the “change your filter” range.  At $10, this is a very inexpensive way to upgrade your filter-changing schedule. 
• FilterScan CleanAlert Smart Air Filter Monitor ($60) has a microprocessor that interprets the pressure differentials and via WiFi, can send you a text message that the filter needs to be changed.  It does, however, need to be hard-wired directly to a 24v power supply, and several customers reviewing it said that this was out of their expertise (DIYers) so it may need to be installed by an HVAC tech.
• Go with a “Smart” Filter:  Filtrete has several types of smart filters that measure pressure differentials and are bluetooth enabled, so that you can monitor filter life from a free app on your smartphone.  When you set the app to connect with Amazon Dash replenishment, you won’t run out of clean filters, either!

Air Flow: Some manufacturers suggest relying on airflow rates to give the true picture of filter status, because measurable pressure drop and temperature climb can come later, when the equipment is about to be damaged.  DPSTelecom and Setra are two of many companies that make air flow sensors but alas, they are mostly used for commercial or industrial systems.  In addition, monitoring a filter via airflow will not work in variable speed air handler systems because airflow will be variable as well. 

Based on the many dirty filters out there and the small number of monitoring products for residential use, we think that HVAC filter monitoring is an underserved market.  If you find another good solution to this problem, let us know!

A little essay on fireworks, air quality and…freedom

As I watched the July 4th New York City fireworks on television, the barges, tugboats and even the bright lights of the city started to fade into the smoke until only the highest and brightest fireworks could be seen at the end of the show.  I had to know, how bad is this for the atmosphere?  Apparently, very bad.  Last year, the July 4th fireworks show caused New York City to have the third worst air quality in the world (IQAir.com).  Normally, NYC has relatively good air quality, as it is ranked 3,628 out of 6,475 cities.  Except on July 4th and 5th.  

Now, in most states cars would not be allowed on the roads without an emissions test, and factories and refineries have emissions limits set by the EPA.  But on July 4th (and also in many cities on January 1), we are free to set off millions of pounds of explosives (in 2021 it was over 150 million pounds in the US).  Is a relatively short display of fireworks really worth the air pollution and body pollution it brings?  

In Boston, the US Army is in charge of “pulling the lanyards”, which means setting off the explosives in time with the orchestra’s famous rendition of Tchaikovsky’s 1812 Overture.  One soldier said that his wife and 2 year old son were in attendance and quickly added that his son would be wearing earmuffs (to protect from the noise).  But what about his little lungs?

According to this 2014 review, copper, lead, sulfur, cadmium, aluminum, manganese, arsenic, iron dust, strontium, barium, antimony and benzene toluene are just some of the dangerous metals and salts released by fireworks.  These different elements are used in fireworks to get the different vibrant colors during explosion.  Because of these toxic metals, being downwind of a fireworks show is much more hazardous than getting caught on the wrong side of a campfire.  Children and adults with asthma,  and those with COPD and other respiratory conditions need to stay upwind and/or use N95 masks, according to Pallavi Pant, senior scientist at the Health Effects Institute (whyy.org). 

It’s not just Americans who go crazy with the fireworks.  Researchers in India discovered that airborne toxins like particulate matter, sulfur dioxide, nitrogen dioxide and ozone stayed in the air for five days after Diwali Festival fireworks. That level was over 2,800% above the limit set by the World Health Organization. (newyorkpost.com).  

With all the bad air effects (not even mentioning the noise trauma for veterans and pets), and our advanced state of technology, when will we have virtual firework shows where we can gather and that last for hours instead of minutes, similar to a virtual aurora borealis?  I suppose each of us values different aspects of our freedom, and enacting those freedoms are part of the celebration.  Personally, I like to celebrate my freedom to eat real meat hamburgers and hotdogs, even though they can be unhealthy for me and the environment.  To each his own…so I guess I won’t be holding my breath waiting for those virtual fireworks!

Could we soon irradiate our own food at home using UV light?

When I first started researching ways to protect against Coronavirus, these little boxes for radiating your phone, keys, etc. seemed to be a very ingenious device.  

They use UV-C light to kill germs on surfaces, claiming only “3 minutes per side” for “99.99% efficiency for maximum protection against microorganisms and airborne allergens.”  One well-known brand name is called “Phonesoap”.  Well, what about our food?  Mold and mycotoxin illness have been around a lot longer than Coronavirus, but I have not seen a solution to eliminate these microbes from food in our homes.  We are (mostly) content to let the food manufacturers and government to handle it.  Shown on food packaging, the Radura is the international symbol indicating a food product has been irradiated. The Radura is usually green and resembles a plant in circle. The top half of the circle is dashed. (wikipedia.org)

Select foods are cleaned by radiation, but it’s a stronger, industrialized process than our Phonesoap example.  This video by the International Atomic Energy Agency does a good job of explaining how it works.  The weapon of choice is x-rays or gamma rays, which are electromagnetic radiation of shorter wavelengths than UV light.  Foods can be sterilized in this way in their packaging, as a cold process that does not affect their color or taste and actually increases shelf life.  There are 3 ways that foods can be irradiated: with X-rays, gamma rays or electron beam (e-beam), which is similar to x-rays (fda.gov).  Besides the obvious foodborne illness that can be present with bacteria or viruses, it can destroy the mycotoxins (toxins produced from different mold organisms) that cause systemic sickness and even cancer (yikes!).  If you are unfamiliar with mycotoxins, here is a post about them.  Recently, I ran across this study that focused on aflatoxins, because of their frequency and potency in causing illness. “Mycotoxins are secondary metabolites of filamentous fungi, dangerous to both humans and animals. The most common mycotoxin-producing genera are Aspergillus, Fusarium, and Penicillium. The family of toxins produced by the fungi Aspergillus flavus and Aspergillius parasiticus pose the greatest danger to animal and human health. Aspergillus flavus is considered to be the most frequent source of aflatoxins in crops. As seed inhabiting fungi, Aspergillus parasiticus can contaminate a wide variety of crops, either before harvesting in the field or after harvest while being handled and processed. Naturally occurring aflatoxins are the aflatoxin B1 (AFB1), the most potent carcinogenic agent known, and the aflatoxins B2, G1, and G2 (aflatoxins B2 and G2 are dihydroxylated derivatives of B1 and G1).”

There are many studies on how irradiation affects mycotoxins, because efficacy of radiation depends on the strain of mycotoxin, strength of radiation, duration of radiation, and the type of food infected with the mycotoxin.  For example, this 2008 study focused on aflatoxin B1 infection and irradiation of food crops (peanut, peeled pistachio, unpeeled pistachio, rice, and corn) and feed (barley, bran, corn).  kGY is a unit of ionizing radiation and the samples were irradiated at 4, 6, and 10 kGy.  It was determined that the high oil content of peanuts served as some kind of protection for the aflatoxin against radiation, because in peanuts, percentage of AFB1 degradation at 10 kGy was not more than 56.6%, whereas, the corresponding value in corn, which contained the lowest oil content, reached as high as 80%. 

I’m glad that manufacturers can use irradiation on mycotoxin-prone food to make it safer to eat, because some of our tastiest foods (spices, chocolate and coffee) are some of the most susceptible to spoilage by mycotoxins!  However, it’s not a process the average person can implement in their home, any more than we can buy an x-ray machine for our own use.  This got me thinking: how effective is UV radiation on mycotoxins?   UV-C is also a non-thermal treatment that doesn’t affect color or taste of the treated food.  One key difference between irradiation by x-ray and gamma ray versus UV light is that the former method can penetrate through packaging and into the food, while UV light only sterilizes the surface of the food and depends on good illumination of the surface.  Or does it?  Another review on UV treatment of various foods admitted at the end that photon energy of the UV light has not been widely studied, and “Photons are likely to penetrate quite deep into the organic matter and thus this technique is not limited to surface effects. The penetration depth depends enormously on the photon energy (or the UV radiation wavelength). Low-energy UV photons (such as those from medium-pressure mercury lamps) penetrate deep into the organic matter, stimulate photo-oxidation, photo-degradation, and photo-elimination (or both), which was found beneficial for the degradation of aflatoxins. Not much research has been performed on the degradation of toxins using high-energy photons.”  

Apparently, the results are varied.  One study on irradiating pineapple sticks with UV-C showed that it did not “significantly affect total viable bacteria, yeast and mould counts. This result confirms the higher sensitivity of bacteria to UV-C light as compared to fungi (Koutchma, 2009)”, and also that the relatively “rough” surface of the pineapple sticks decreased the efficacy of irradiation.  Increasing the intensity of the light also did not increase degradation of the yeasts or molds.  However, the pineapple sticks, once they were treated and packaged in PET/EVOH/PE plastic trays, sealed with a PET/PE film and stored at 6 °C to simulate storage of fresh-cut fruit along the refrigerated chain, grew less yeasts than the control samples, indicating that UV-C irradiation helped to lengthen storage life.  Molds were not affected between the control and irradiation samples, presumably because the pineapple off-gasses as it is stored, creating an anaerobic environment. 

In this 2008 study in which two levels, mild and strong, UV radiation was used against feed-contaminating mycotoxins, even the mild radiation was effective in destroying the two types of mycotoxins within 60 minutes, but the stronger radiation performed more rapidly.  

A review of many studies was made to compare UV, ozone and ammonia treatment of foods with mycotoxins for inactivating aflatoxins.  Here are some results of the UV radiation studies:

• UV irradiation of 15 min of aflatoxin-contaminated semolina (wheat grain) could lead to the complete degradation of AFB1. A germicidal UV lamp with 30 W power providing UV-C radiation at 254 nm was used as a light source, and 100 g of the semolina layer of 1 cm thickness was exposed to the UV light at a distance of 15 cm.
• In hazelnuts that were artificially inoculated with Aspergillus, the effects of a 254 nm UV-C treatment were measured on aflatoxin production.   A 2-log reduction in Aspergillus spp. counts and a 25% reduction in aflatoxins B1 and G1 were obtained with a 6 h (2 h periods repeated 3 times) UV-C (9.99 J/cm2 ) treatment (2 log reduction is equal to 99% reduction). 
• Another approach to UV light irradiation is “pulsed light” technique, which has the advantages of a broad UV spectrum, a short duration, but high peak power.  For example, instead of minutes or hours of UV treatment, pulsed light is used for seconds.  Again, some strains of mycotoxins are more degraded by pulsed light than other strains, and in treatment of a water solution of mycotoxins, ochratoxin and aflatoxin B1 were more degraded than zearalenone and deoxynivalenol.  In a study of rough rice and rice bran which were inoculated to grow aflatoxin B1 and B2, it was found that irradiation of the rice bran was more effective ( 90.3% and 86.7% on AFB1 and AFB2 respectively) than the rough rice (75.0% and 39.2%).  This may be due to the surface characteristics, because rough rice is the whole rice kernel including the hull, and the rice bran is brown rice, which has the hull removed but still contains the bran. (feedipedia.org)  Therefore, the stage of food processing is important for deciding when to apply radiation. 
• Humidity of the foods under study is also important for mycotoxin degradation.  A study of nuts that were inoculated with Aspergillus flavus, Aspergillus parasiticus, and Penicillium, showed that greater humidity = greater degradation.  “The fungicidal activity of UV-C radiation was found to be more pronounced in the nuts treated at the higher 16% moisture level, with levels of efficiency in the following order: walnut > almond = pistachio > peanuts. A 45 min treatment resulted in 87% and 96% degradation of AFB1, depending on the moisture level, with the maximum reduction seen for almond and pistachio.”

At the end of this review, the authors confessed what was growingly apparent to me: 1. The destruction of toxins remains both a scientific and technological challenge.  (In effect, it’s hard to determine the best standard treatment (intensity of light, duration and distance from food)  when type and level of mycotoxin, type of food, and humidity level all come into play!)   2. The reported treatment times are prohibitively long for industrial application.  (It should be obvious that treatment times in hours are not feasible for the many tons of feed and food processed every year, although pulsed light treatments of seconds may be.)

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