As the nation and world grapple with the COVID-19 pandemic, Clark County vehicle traffic has been reduced. With the resort corridor shut down and many locals complying with Gov. Steve Sisolak’s stay-at-home order, Las Vegas Valley roadway traffic is noticeably less crowded. Is that reduction in vehicle emissions having an impact on air quality? Recent data gathered by the County’s Department of Environment and Sustainability indicate less overall pollutant emissions in the region, with much of it likely due to fewer vehicles on the roads.
“We are seeing reductions in PM2.5—small particulate matter—and nitrogen dioxide (NO2) when you compare data from the first half of March to the second half,” said Environment and Sustainability meteorologist Paul Fransioli. “Data shows about a one-third decrease in those pollutants from February to March.”
The conclusion stems from analysis of data from two air quality monitoring stations—one located at Jerome Mack Middle School on East Karen Avenue and a near-roadside station monitoring vehicle emissions at Rancho Drive and Teddy Drive. Levels for NO2 and PM2.5 decreased from March 1-16 compared to March 17-23. Both pollutants are considered harmful to health and the environment by the U.S. Environmental Protection Agency.
According to the EPA, air pollution emitted from the transportation sector (cars, trucks, commercial aircraft and railroads) contributes to smog and poor air quality. Pollutants that contribute to poor air quality include particulate matter (PM) and nitrogen oxides (NOX).
Other findings include:
· • Based on five years of air quality index data (2016 – 20), particulate matter, nitrogen dioxide and ozone are down slightly in March 2020 as compared to March in the years 2016 – 19.
· • There were 16 days in February with MODERATE overall air quality, according to the Air Quality Index (AQI), compared to one MODERATE day in March.
Though more study is required to determine how much impact the reduced vehicle traffic is having on the pollutants in the air, DES officials believe these results are consistent with similar air quality findings around the country. And, Fransioli points out, weather patterns were consistent throughout the period. What does this mean for the region’s overall air quality.
Less Vehicle Traffic During COVID-19 Situation Yielding Less Air Pollution, Data Suggests, cont.
“It’s too early to tell how much impact this will have on ozone this summer. We know for a fact that Clark County’s air quality has been good and improving since before the stay-at-home order,” Fransioli said. “With the exception of wildfire summers, our air quality has steadily improved over the past 15 years or so.”
Particulate Matter and Nitrogen Dioxide
Particulate matter and nitrogen dioxide are classified as criteria pollutants by the U.S. Environmental Protection Agency. The Department of Environment and Sustainability monitors the region’s air quality and enforces all federal, health-based standards as mandated by the EPA and the Clean Air Act. Particulate matter is dust, smoke, soot and other particles in the air and is monitored and regulated in two sizes: PM10 (larger) and PM2.5 (smaller). NO2—nitrogen dioxide—is produced by the burning of fuel and contributes to the creation of particulate matter in the air as well as ground-level ozone, which is a toxic gas.
About the Department of Environment and Sustainability
The Department of Environment and Sustainability is the air pollution control agency, regional Endangered Species Act compliance program, and sustainability office for all of Clark County, Nevada. Established as the Department of Air Quality by the Clark County Commission in 2001, it was renamed in 2020 and is comprised of three divisions: Air Quality, Desert Conservation Program and Office of Sustainability. Through the work of these three divisions, DES is ensuring the air we share meets healthful, regulatory standards, administering the County’s Multiple Species Habitat Conservation Plan and addressing climate change.