[Smart working and active mobility for reducing CO2 emissions from the home-to-work commute: the results of the Climactions project].

to estimate CO2 emissions for different commuting modes before, during, and after the COVID-19 lockdown, and define scenarios to assess their impact on the environment and health. cross-sectional study using data retrieved from a survey. the study included anonymous participation from both researchers involved in the Climactions project and the general population; the questionnaire was made available through social media. Information was gathered on the transportation modes used to commute, the distance travelled and travel times before, during, and after the COVID-19 emergency, and proposals for actions/solutions to enhance sustainable commuting in urban areas. the amount of CO2 emissions due to different commuting modes during various stages of the pandemic was estimated based on vehicle-specific emission coefficients provided by the European Environmental Agency, taking into account the average number of passengers per vehicle. Sustainable commuting scenarios were also proposed, including active transportation (walking, cycling, etcetera). the online questionnaire was filled-in by 2,904 persons, predominantly women (62.3%) and residents in Northern Italy (44.6%). Over 80% of the respondents were aged over 40 (0.7% <25 years). On average, the distance travelled on a daily commute was 23.6 km (median: 13 km), with longer distances in the Southern Regions (average: 38.2 km, median: 20 km). The average per-capita CO2 emissions were 2 kg per day in the pre-pandemic situation. The reduction in commuting during lockdown periods led to a significant decrease in estimated CO2 emissions, with an average per capita reduction of about 100 grams per day. From September 2020, the increase in smart working among respondents still allowed for a reduction in estimated CO2 levels, despite an increase in emissions from private vehicle use (1.5 kg per capita per day). Considering sustainable scenarios, a 15-minute walk during the daily commute would lead to a reduction in estimated CO2 levels of up to 0.7 kg per capita per day. Regarding the statement that "improving air quality in cities and reducing greenhouse gas emissions are useful actions to combat climate change", 94% of respondents strongly agreed. in Italy, road transport accounts for approximately 25% of the total CO2 emissions. The lockdown provided a natural scenario for reducing emissions in urban areas, and the implementation of smart working was associated with a decrease in CO2 emissions due to reduced commuting. However, it is crucial to promote sustainable and active transportation modes for daily commuting such as walking and cycling, also considering the significant health co-benefits.