The air is cleaner.
As businesses temporarily close and people limit travel amid the coronavirus pandemic, data gathered by the Clark County’s Department of Environment and Sustainability points to signs that with fewer vehicles on the roads, Southern Nevada’s air quality is improving.
“Those numbers were generated in late March when we started noticing these apparent decreases and wondered if it was associated with emission travel or overall emissions,” Fransioli said. “We did some number crunching and confirmed that air quality between early and late March did improve.”
The data comes from air-testing instruments positioned near ground level that measure concentrations of multiple pollutants as part of legally mandated air quality standards under the Environmental Protection Agency and the Clean Air Act.
Particulates pollution, like nitric dioxide and ozone, decreased this month around metro Las Vegas compared with concentrations a year ago, according to 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.
“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 end of March saw a marked decline in particulate matter and nitrogen dioxide compared to the first two weeks of March, and while there were 16 days in February with inferior “MODERATE” overall air quality, according to the Air Quality Index (AQI), March only had one.
Fransioli said it’s still too early to measure significant reductions in Nevada, adding that meteorological factors such as wind, air pressure, and rain have a big impact on air pollution. But after comparing levels of particulate matter for March starting in 2016, he said this year’s pollution is at the lower end.
With dramatic reductions in people driving to work and buses transporting children to school, levels of nitrogen dioxide — the noxious gas emitted from burning fossil fuels — are certainly guaranteed to go down.
The transportation sector is the largest contributor of greenhouse gas emissions, according to he EPA.
Traffic volume along the Interstate 15 dropped by about 70 percent in the last three weeks compared to the same time last year, according to data from the The Regional Transportation Commission of Southern Nevada. Interstate 215 saw a traffic reduction of almost 50 percent and Boulder Highway dropped by nearly 40 percent.
In Clark County, about 880,000 people drive to work every day — 779,226 by themselves and 96,910 in carpools, according to U.S. Census data from the 2018 American Community Survey, statewide closures and stay-at-home orders have dramatically reduced the number of people traveling to work in the last few weeks.
School buses contribute to urban air pollution as well, but have been sidelined due to the closure of schools across the state. During the 2017-18 school year, a total of 2,789 school buses traveled a total of 38,080,144 miles. Most of those buses (1,805) are in the Clark County School District and most of those miles (26,979,334) were driven in the Clark County School District.
“Air quality levels are definitely associated with the amount of emissions from pollutants and in our area a lot of that is vehicle related,” Fransioli said. “With a lot less people driving around there’s a lot less emissions and pollution levels in this period.”
Air travel is a major contributor to smog and poor air quality according to the Environmental Protection Agency. McCarran airport is the nation’s 9th-busiest airport but has reduced flights due to the onset of COVID-19.
A spokesman for the airport said that while they will not have data measuring the impacts of COVID-19 on air travel starting in March until the end of the month, they are anticipating a significant impact given adjustments airlines have made for economic reasons along with announced travel restrictions due to coronavirus.
Pinpointing the extent to which reductions from less driving, less flying or less power plant activity will impact pollutants in the air requires further study, Fransioli said, but officials with the Department of Environment and Sustainability believe these results are consistent with similar air quality findings around the country and internationally.
In China, as a result of people working from home, a drastic reduction in flights, and shuttered industries, air pollution dropped by roughly a quarter in February. Satellite images showed a similar situation in northern Italy after the government introduced stringent measures to stop the coronavirus spread.
“We will be keeping our eye on this as time wears on here. We’ll have more definitive ideas on some of this stuff as it plays out over time,” Fransioli said.