Heather Murgatroyd, RT
The hot topic for the summer of 2023 appears to be air quality. The air quality for my hometown was rated “unhealthy” recently. This led me to wonder, ‘what does that actually mean?’ What are they measuring? Who is doing the measuring and reporting? What does this mean for people with respiratory problems in an area of poor air quality?
The US Environmental Protection Agency (U.S. EPA) measures air quality trends via monitors positioned across the country and they set National Ambient Air Quality Standards that identify pollutants considered harmful to the public and environment and publish reports on their findings.
The EPA publishes the Air Quality Index Report, https://www.epa.gov/outdoor-air-quality-data/about-air-data-reports#aqi. This is an annual summary of overall air quality and accounts for pollutants like carbon monoxide (CO), nitrogen dioxide (NO2), ozone (O3), fine particulate matter (PM2.5), and particles with a diameter of 10 microns or less (PM10). The report shows the number of days reporting AQI, number of good, moderate, unhealthy for sensitive groups, unhealthy, very unhealthy, and hazardous days. The range is 0-500. The higher the number, or AQI value, the greater level of pollution and correspondingly greater health concerns.
The EPA Air Quality Index Daily Values Report is a tool where you can search by location, year, and pollutants. You can enter your city, if listed, or county and the pollutant you’d like to check, ozone for example. Then choose the year. The report will show the daily AQI value and the category it falls under (good, moderate, etc.). My area of the country is, and has been, in the unhealthy category for several days this summer. However, it has been improving and moved into the good to moderate zone. The air quality index is forecasted as well; this allows people to plan around it if they are compromised and affected by poor air quality.
Air pollution can be naturally occurring, such as wildfires, however the industrial revolution created a global air pollution problem. Traffic-related air pollution, also known as TRAP, is particularly troublesome for the respiratory system. TRAP is made up of PM2.5, PM10, NO2 and black carbon.
Many patients we work with in respiratory struggle when the air quality is poor. In COPD patients, air quality has been shown to increase the mortality rate, both short and long-term exposure. There have been a variety of studies on whether long-term exposure to air pollution impacts lung function in COPD patients, and the results have been mixed. A study from China showed short-term exposure to PM2.5 and PM10 concentrations decreased the forced vital capacity (FVC) by 3.3 and 2.1% respectively, whereas a study out of London that investigated short-term effects did not find an association with decreased FVC. However, studies from Spain, USA, and China have shown an association between increased air pollution and COPD hospital admissions. It is known that exposure to particulate matter causes increased inflammation in airways which are chronically inflamed, increasing the potential for exacerbation of COPD symptoms.
For individuals with COPD, outdoor activities should be reduced or delayed when levels are high and masks such as N95 may prove helpful against air pollutants. However, most of the information on the benefits of wearing a mask to protect against air pollutants have been done on healthy individuals, not those with COPD.
For adults and children with asthma, outdoor pollutant exposure can increase symptoms, exacerbations, may decrease lung function and have a negative impact on outcomes. TRAP may contribute to asthma in children and have a negative impact on outcomes in adults and children. The Prevention and Incidence of Asthma and Mite Allergy (PIAMA) study showed early life exposure to air pollution and TRAP is associated with increased incidences of asthma in children up to 20 years of age. There are many other studies which show higher incidences of asthma in children with prenatal and postnatal exposure. Air pollution aggravates asthma and can also cause new-onset asthma. The epithelial integrity is disrupted when exposed to various components of air pollution. In response, inflammation, airway hyperreactivity and lung injury occur. Each of the components of air pollution measured in the Air Quality Index, NO2, PM, O3, CO, as well as carbon dioxide CO2, sulfur dioxide SO2, have been shown to contribute to poorer asthma outcomes: increased exacerbations, hospitalizations, and increased emergency room visits. Minimizing the asthmatic patient’s exposure to air pollutants is a major step in managing asthma during times of poor air quality. The EPA app, AIRNow, provides real-time air quality information. Monitoring the information in a particular area allows patients to make informed choices while moving through the day. For example, if air quality is reported to be poor, wear an N95 or take a low-traffic route while traveling. Minimizing or avoiding outdoor activities during poor air quality days may be helpful.
Exposure to indoor air pollutants such as smoking, secondhand smoke, wood heat sources, wood or coal cooking sources also create an environment of poor air quality. Fortunately, there have been positive strides in ensuring cleaner indoor air, such as smoke-free indoor air laws. and the installation of non-polluting heat sources that lower levels of NO2 in the homes of children with asthma. These measures have been shown to reduce symptoms, exacerbations and improve asthma outcomes.
I don’t recall having so many discussions about air quality before this summer. The common conversation starter “It is so hot!” has been replaced with “The air quality is bad today.” I hope the rise in awareness of the impact of poor air quality will bring about more efforts to take measures to improve it.
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Tiotiu AI, Novakova P, Nedeva D, Chong-Neto HJ, Novakova S, Steiropoulos P, Kowal K. Impact of Air Pollution on Asthma Outcomes. Int J Environ Res Public Health. 2020 Aug 27;17(17):6212. doi: 10.3390/ijerph17176212. PMID: 32867076; PMCID: PMC7503605.