Sources of particle number concentration and noise near London Gatwick Airport

•Particle size distributions and noise levels were measured at two locations near Gatwick airport in 2018–19.•Peak particle number concentrations (PNC) were highest at the site closer to the runway.•Source apportionment identified six factors at each site with the airport source factor contributing 17%.•The largest source of noise above background was associated with sources of fresh traffic and urban particles depending on the site.•PNC is unlikely to be an important confounder in epidemiological studies of aircraft noise and health near airports.