Tag Archives for " air pollution "

It’s not the heat, it’s the air pollution!

It’s not the heat, it’s the humidity air pollution!

Decades ago, when the meteorologists predicted extreme heat, it seemed they only advised on the necessity to stay out of the sun, drink more water, and cool off more frequently (stay in the pool, yayyyy!).  Now, heat advisories come with more sinister warnings about air pollution levels, and the outdoors are less fun.  How did that happen?  The answer lies in meteorology and chemistry, all cooked up in our atmosphere.

Low-pressure systems are quite famous for moving rapidly across the US and bringing devastating weather like severe thunderstorms, hail and tornadoes.  They can also sweep pollutants like smoke and smog to other states.  High-pressure systems, on the other hand, typically cause stagnant air, which can concentrate pollutants over one area.  (scied.ucar.edu)  A “Heat Dome” is an area of high pressure that parks over a region like a lid on a pot, trapping heat. (National Geographic) A Heat Dome caused about 600 deaths in June 2021 in the Pacific NorthWest as a 1-in-1000-year event.  The heat, which broke Portland’s all time record of 107 degrees, was bad enough, but extreme heat combined with stagnant air during a heatwave increases the amount of ozone pollution and particulate pollution. (metone.com)  Here is where the chemistry comes in.

“Ground-level ozone pollution forms when heat and sunlight trigger a reaction between two other pollutants, nitrogen oxide and volatile organic compounds — which come from cars, industrial facilities, and oil and gas extraction. High temperatures therefore make ozone pollution more likely to form and harder to clean up. Drought and heat also increase the risk of wildfire, which can make air quality worse as smoke drives up levels of fine particulate matter — also known as PM2.5, or soot...Both ozone and PM2.5 carry major health risks. Ozone can cause acute symptoms, including coughing and inflamed airways, and chronic effects, including asthma and increased diabetes risk. PM2.5 exposure can lead to an increased risk of asthma, heart attack, and strokes. Globally, long-term exposure to PM2.5 caused one in five deaths in 2018, including 350,000 deaths in the United States.” (Heat waves can be life-threatening for more reasons than one)

Because of the increase in cars and industry, extreme heat forecasts are not just requirements to have bottled water and popsicles on hand and check that our elderly neighbors’ air conditioning is working.  It’s a time to make sure that those who have asthma, heart and vascular conditions stay indoors, and that you take the proper air pollution precautions, too. 

Unlike outdoor air filled with wildfire smoke, ozone and smog are not as visible and may not affect everyone immediately, but they are dangerous pollutants and shouldn’t be allowed in our homes.  Here are some steps you can take to prepare for that heatwave, and the resulting air pollution that often accompanies it!  

  • Seal doors and windows with weatherstripping, caulk and door sweeps.  

  • Find out how to adjust your HVAC system accordingly: you’ll want to close the fresh air intake and change over to recirculation, no matter whether you have central AC, a window air conditioner or portable air conditioner.

  • Purchase extra MERV 13 filters for your HVAC system, to be used on poor air quality days (caution: read our post on HVAC filters first, as using a filter with too high MERV rating can damage your system). 

  • If you live in an apartment building or condo with little control over the HVAC, consider purchasing vent filter material so you can place them in the vents into your space.  The filter material can prevent smaller particulates in smog from entering.  Carbon vent filter material will neutralize many VOCs as well.

  • Purchase a HEPA air cleaner (non-ozone producing type) and be sure to have an extra filter or two on hand.  The use of a HEPA filter will take much of the damaging fine particles out of the air you breathe!  Whenever there is bad air quality outside, run the cleaner/purifier on high for an hour and thereafter at "quiet"/medium setting (Wirecutter).  You can check out our post on standalone HEPA filters as a purchase guide.  If you can't purchase one, make one: there are many videos and instructionals online for DIY air cleaners; most only require one or more filters, a box fan, and some cardboard and tape.

  • Keep a stash of N95 respirator masks on hand.  These are a good source of protection if you have to go outside, or if power is cut to your home and indoor air quality gets bad as well.  The “95” means it blocks out 95% of particulates.   

  • Keep canned and non-perishable food on hand, so that you don’t have to cook during periods of bad air quality.  Cooking indoors increases small particulates and vapors in the air, and you won’t want to turn on your stove exhaust, as that will draw polluted outdoor air into the house.

  • If air quality is very poor (check next point), you’ll want to evacuate to a place with clean, filtered air, like indoor malls, libraries, community centers, civic centers and local government buildings (sfgate.com). 

  • Check your local air quality and receive updates from airnow.gov . Using an Air Quality Index (AQI) as a measuring tool ranging from 0-500, your local forecast and larger maps can be color coded to show whether an area is good (green), moderate (yellow), unhealthy for sensitive groups (orange), unhealthy (red), very unhealthy (purple), and hazardous (maroon).

Photo by Call Me Fred on Unsplash

Surround yourself with trees, and your heart will thank you for it!

Surround yourself with trees, and your heart will thank you for it!

We tend to surround ourselves with what brings us comfort.  It might be your favorite music, your favorite color, your favorite art, and even your favorite pillow or type of sheets when you go to bed.  What if your source of comfort actually made you healthy?  Where you live and what you do with your property is an important choice that can affect your heart health.

We’ve been told for some time that plants have psychological and physical benefits–just look at this page of studies!  A new study (2021) correlates the proximity of living near trees, to arterial stiffness.  According to a 2010 textbook, “Arterial stiffness describes the rigidity of the arterial wall. In the last decade, there has been increasing interest in the potential role of arterial stiffening in the development of cardiovascular disease in adults.”  In addition, the 2015 book Early Vascular Aging states, “Arterial stiffness is a hallmark of arterial aging. As with all other organ systems, changes in the vascular system are induced over time.”  This is very important, because cardiovascular disease (CVD) is the leading cause of death worldwide.  Although many associate CVD with genetics, “recent estimates suggest that up to 70%–80% of CVD burden could be attributed to non-genetic environmental factors, such as lifestyle choices, socioeconomic status, air pollution, lack of surrounding greenness (2), and residential characteristics (2018 study). Indeed, emerging evidence has shown that living in greener areas results in improved health and is associated with lower mortality (2016 study on mortality of women, 2016 study on green spaces and mortality), and reduced CVD risk (2019 study, 2012 study).”

How does the “proximity to greenness” cause these positive effects?  Is it because vegetation promotes exercise or a healthier lifestyle?  Or because it reduces stress?  Trees do have the ability to filter and block particulate matter, and it has been shown that people living in greener areas were exposed to lower levels of volatile organic compounds (2020 study).The 2021 study focused on reduction of pollution, particularly ozone and PM, due to plants and trees in specific radii around the home, and the effect of the reduced pollution on the participants’ arterial data.

What is proximity to greenness?  The study used satellite-derived normalized difference vegetation index (NDVI) for a 200-m and 1-km radius around each participant’s home; the 200 m range was directly around the home, while the 1 km radius indicated walking distance.  Data on ambient levels of pollutant concentrations were retrieved from regional EPA-validated monitoring stations in the Louisville, KY region, that report daily pollutant levels.  The data included PM2.5, PM10 and ozone. 

Here are some specific results: 

  • At smaller radii (200 m) buffer around the home, inverse associations between standard deviation of NDVI and augmentation pressure, aortic pulse pressure, and aortic systolic pressure were observed (as greenness goes up, arterial stiffness goes down). 
  • Significant positive associations between several arterial stiffness metrics and pollutants in low greenness areas were observed, whereas the association between pollutants and arterial stiffness measures was not significant in areas of high greenness (as greenness goes down, arterial stiffness goes up).
  • Arterial stiffness was only associated with NDVI at the 200-m radius, but not the 1-km radius, giving support to the theory that because roadways are sources of pollutants, street trees within a 200-m radius around the individuals’ residence would be more relevant in blocking exposure to pollution. 
  • It was shown that ozone, but not PM2.5, was significantly associated with higher augmentation index (increased arterial stiffness). This suggests that ozone-induced effects on arterial stiffness are independent of PM2.5 exposure and potentially stronger.
  • In addition to modifying the effects of air pollution, proximity to greenness may improve cardiovascular health by decreasing mental stress. Exposure to natural outdoor environments has been found to be associated with better mental health and could facilitate stress reduction (2017 study), and neighborhood greenness is associated with lower levels of self-perceived stress and depression (2018 study), particularly in older adults. In our work, we have found that higher levels of residential greenness are inversely associated with urinary levels of the stress hormone—epinephrine (2018 study). Hence, it seems plausible that some of the effects of greenness on arterial stiffness may be mediated by a reduction in mental stress. 

How can we apply these findings to our own lives?  Since “greenness” is good for our bodies, plant as many trees and shrubs as possible, and encourage your neighbors to do so as well, by letting them know how good it is for them and the neighborhood.  The 200 meter radius is equivalent to 656 feet, which when converted to square feet (656 x 656) is equivalent to 2.3 acres.  That is a big green space that not many people own for their own property, but when spread out over a neighborhood or nearby park, it is certainly achievable.  If you live near a busy highway or road, definitely plant as much green area on the border of your property as you can. 

Some tree species are better than others at absorbing pollution, because as we’ve mentioned in other posts, 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).  You definitely want the former type!   Here are some tips:

  • A free online tool called i-Tree Species helps you to select the best plants depending on desired hardiness (after all, if the plant won’t live in your area it won’t do much good to introduce it), mature height and environmental factors such as air pollution removal and air temperature reduction, among other factors.
  • In one recent study, Barbara Maher and colleagues at the University of Lancaster tested the ability of nine tree species to capture PM in wind-tunnel experiments. Silver birch, yew and elder trees were the most effective at capturing particles, and it was the hairs of their leaves that contributed to reduction rates of 79%, 71% and 70% respectively. (bbc.com)
  • Conifers, such as pines and cypresses, are the best pollution filters, while London plane, silver maple and honey locust ranked above average too, according to Jun Yang, an urban ecologist at the Center for Earth System Science, Tsinghua University in Beijing. (bbc.com)
  • If you have the opportunity to give input for city-wide greenery initiatives, be aware that taller species of trees can trap pollutants in areas, so sometimes shrubs are better when narrow streets are surrounded by tall buildings. 
  • If you do have a large property or even a city park to design, remember to diversify the species so that certain pests or adverse conditions like too much or too little rain will not wipe out the whole property.  

In all, green spaces mean gold stars for your heart health, so it’s time to start seeing green!

Photo by Pankaj Shah on Unsplash

How droughts can even impact your air

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)

Photo by redcharlie on Unsplash

Some small plants can make a big difference!

Some small plants can make a big difference!

I have to admit that this post was inspired by an episode of Alone.  One of the participants boiled “Reindeer Moss” to eat.  That made me wonder, is moss good for anything else?

You will never see some of the best plants at filtering air pollution when strolling through the aisles at the local garden center or nursery.  Why?  Well, they just aren’t…popular.  If we only knew what they could do, maybe they would take front and center stage!

Moss: Ok, you may see moss at the garden center but it’s typically only used as a decoration to cover bare soil.  A couple of German entrepreneurs think it has a lot more to offer than decoration.  They have launched their business to bring moss walls to cities across Europe and around the world.  Moss walls are available in three configurations for installation in temporary or permanent displays.  Why moss?  

  • The moss walls filter up to 82% of fine dust from the air flowing through them.
  • Water vapor evaporates from the leaf surface of the moss, creating a cooling effect of up to 4 degrees C (about 7 deg F)
  • The moss wall also removes up to 355 kg of CO2 every year.

To make the most out of this amazing plant, fans draw in air through the moss and sensors monitor the health of the plants, providing automatic watering.  Sounds like we could use moss walls in the US!

Plankton: Unless you are a fish enthusiast, plankton is not usually very convenient to keep in your home.  Enter the Bio Orb, a glass container of bioluminescent phytoplankton, plankton that can produce light at night and fresh oxygen during the daytime.  Pyro Farms, is the maker of the Bio Orb, a glass sphere with a flat bottom and a specially designed stopper to allow air exchange but prevents excessive evaporation.  The Bio-Orb provides the ideal environment for growing PyroDinos (the bioluminescent phytoplankton) at home, in the office or at school.  (pyrofarms.com)  Scientists estimate that all plant-plankton (phytoplankton) are responsible for more than 70% of the air we breathe, so keeping plankton in your home, school or office offsets your personal carbon output. (earthsky.org)

Source: (pyrofarms.com)

Lichen: I remember learning about this plant in biology and probably geography.  Pictures of reindeer munching on lichen in the tundra come to mind.  What I don’t remember learning is that it’s not actually just a plant, but a combination of two or three organisms: a fungus and green algae or cyanobacteria, often both.  The fungus provides the structure that determines the shape of the organism, while the algae and/or cyanobacteria  provide photosynthesis to feed both the fungus and the algae/bacteria.  There are three types of lichen growth, which have various abilities to absorb pollutants and concentrate heavy metals (hobbyfarms.com).  They are like natural sensors in the environment to tell us about the pollutants in the air. 

  • Crustose lichens are flat; since they have the least amount of surface area to absorb pollutants, they are the most abundant.

  • Foliose lichens have a leafy shape and tend to stand off the substrate (wood, rock, etc) a bit.  They have a little more surface area so are a little less tolerant to air pollution.

  • Fruticose lichens are like tender, miniature shrubs, having the most surface area.  These only thrive in pristine areas with minimal air pollution.  

Next time you are on a walk, look for moss and lichen.  They are small plants that can make big contributions to healthy air!

Two "Moss Trees", source greencitysolutions.de

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