the effect of coronavirus restrictions on air quality and exiting daily traffic

Background and objectives: this research attempted to analyze the negative andpositive aspects of coronavirus: its effect on air quality and traffic volume. the samplecity of this research was tehran and transportation behavior toward the coronavirusand minor quarantines in specific.methods: six indices were considered for tehran city in two consecutive years (inquarantine period): carbon mono-oxide, nitrogen dioxide, sulfur dioxide, particulatematters, air quality index, and daily traffic volume, which depart from tehran city to otherdestinations. daily traffic volume changes were examined for four roads separately, andtotal departed trips were also investigated. this comparison was made graphically andstatistically by using the regression model and one-way t-test.findings: results showed that from 20th february to 19th march, the average ofproduced co, no2, and pm10 decreased in 2020 compared to 2019, but other indicesrelated to air pollution were increased in 2020. the average daily traffic in existing roadsof tehran city was declined significantly in 2020. regression models and a one-wayt-test showed that the growth rate of emission production was higher in 2019 comparedto 2020. also, this rate for daily traffic volume was higher from march 20 to april 19 of2020 compared to 2020.conclusion: the regression model on indices showed valuable results. for instance,the o3 emission slope in the second month reduced from 0.6 to 0.5; however, theexiting traffic of tehran city reduced by 47 percent that indicates the higher residentpopulation of tehran city compare to the last year.