This dataset contains atmospheric nitrous acid (HONO) combined measurements made at the Institute of Atmospheric Physics land station (IAP-Beijing) site, during the summer and winter APHH-Beijing campaign for the Atmospheric Pollution & Human Health in a Chinese Megacity (APHH) programme.

This combined dataset consists of a single mean time series of HONO mixing ratio (ppb), and associated min/max values determined from the datasets of 4 instruments that measured HONO at IAP at ground level. The data are averaged over 1 hour, the time stamp represents the start time of each averaging period.

The instruments included in the combined dataset are the University of Birmingham commercial wet-chemical LOPAP instrument (Heland et al. 2001), Institute of Chemistry, Chinese Academy of Sciences custom built wet-chemical instrument (Tong et al. 2016), and two custom built Broadband Cavity Enhanced Spectrophotmeters (BBCEAS) from the University of Cambridge (Kennedy et al. 2011) and Anhui Institute of Optics and Fine Mechanics (Duan et al. 2018).