‘When we have poor air quality we see more patients in the ER and in clinic with respiratory complaints, especially those with underlying lung diseases like COPD and asthma.” Dr. Geoff Maly, Winding Waters Clinic.
Air pollution consists of particulate matter (PM) plus gasses such as ozone, nitrogen dioxide and sulfur dioxide. Extremely small particulate matter is referred to as PM2.5 because particle diameter is less than 2.5 microns; small enough to be inhaled, trapped in the terminal air passages of the human lung and then absorbed. Most PM2.5 comes from combustion of fuels including gasoline, diesel and wood.
Once particles and gasses are absorbed they can trigger inflammatory reactions and acute and chronic problems. Whether an individual will suffer health consequences is complex, depending upon age and underlying health, daily activities, the type of chemicals present, the duration and amount of exposure and genetic susceptibility.
Adverse health consequences from air pollutants are clear. The New England Journal of Medicine (NEJM), perhaps the world’s most prestigious medical journal, published the Harvard “Six Cities Study” in 1993 that found people living in polluted environments had shorter life spans than those in less polluted cities. In August 2019 the NEJM published a study by 49 authors from around the world, “Ambient Particulate Air Pollution and Daily Mortality in 652 Cities”. The study found a statistically significant association between increasing concentrations of PM2.5 and increasing rates of deaths from respiratory and cardiovascular diseases throughout 16 countries or regions.
The 1993 NEJM study (above) and others supported legislation, including the 1990 Clean Air Act, to improve air quality in the US. The Environmental Protection Agency (EPA) developed the Air Quality Index (AQI) to provide local air quality data and recommended action to avoid adverse health consequences. EPA was authorized to enact regulations limiting automobile tailpipe emissions, limits on industrial pollution and similar activities.
The EPA provides daily AQI for the US at AirNow (https://airnow.gov/). The Oregon Department of Environmental Quality reports daily AQI including PM2.5, ozone and nitrogen dioxide from monitors throughout Oregon, including Enterprise (https://oraqi.deq.state.or.us/home/map). Depending on concentrations and types of pollutants, the AQI is reported in one of 6 categories, from “Good” (concentrations less than 50 units; little or no risk) through “Hazardous” (concentrations over 300 units; health emergency likely affecting the entire population).
Air quality in Wallowa County, like much of rural Oregon, is typically “good”. A major exception is during a severe fire season. According to Peter Brewer, Air Quality Attainment Coordinator at DEQ in Bend, the 2017 fire season in Wallowa County, when haze was oppressive for days, raised AQI values to 100-300 rivaling a typical day in many cities in India. At levels of 100-150, sensitive groups including those with underlying pulmonary diseases and some healthy persons may have worsening health. When AQI is 150-200, everyone should reduce prolonged exertion and time outside. At 200-300, everyone should limit exposure by staying indoors, wear effective masks or take other measures.
Another important pollutant is diesel exhaust, especially for persons with chronic occupational exposure such as workers near diesel powered vehicles and equipment. Diesel exhaust is mostly composed of PM2.5 particles (soot) and gases that have been linked to a large number of health problems, including pulmonary, cardiovascular, central nervous system diseases and cancers. Children and the elderly are most likely affected. Oregon has multiple programs to reduce diesel exposure. www.oregon.gov/deq/aq/programs/Pages/Diesel-Health-Effects.aspx. An OPB article allows you to enter a zip code to estimate local diesel pollution. (www.opb.org/news/article/diesel-pollution-portland-reduce-lewis-clark/) For Joseph, “diesel pollution is among the lowest levels in the country.”
The science linking air pollution to human diseases has been developed over decades resulting in US standards that guide the world. However the current administration is aggressively undermining the scientific infrastructure supporting and enforcing these standards. For example, career scientists with the background and training to interpret pollution data are being replaced with industry consultants. Also, proposed changes in the clinical science required to influence policy would likely nullify the two NEJM studies reviewed above, and much of the remaining literature, further relaxing current air quality standards. www.nytimes.com/2019/11/11/climate/epa-science-trump.html
The science behind regulations to limit the level of allowable air pollutants is beyond the abilities of most of us to truly comprehend. For me, there is a simple test. Those in favor of relaxing pollution limits appear to me to be motivated by a desire to decrease expenses associated with pollution control and increase profits. Those in favor of maintaining or tightening allowable pollution limits appear to me to be motivated by a belief in the scientific process leading to improved health in our citizens.