Editing IPCC:AR6/WGI/Chapter-6 (section)

==== 6.6.2.2 Residential and Commercial Cooking and Heating ====

<div id="h3-18-siblings" class="h3-siblings"></div>

The residential and commercial sector is associated with SLCF emissions of carbonaceous aerosols, CO and NMVOCs, SO <sub>2</sub> and NO <sub>x</sub> , and can be split by fuel type (biofuel or fossil fuel) where residential fossil fuel is also associated with CO <sub>2</sub> and methane emissions (Section 6.2.1).

The net effect of residential CO and NMVOC emissions is warming and that of SO <sub>2</sub> and NO <sub>x</sub> is cooling of the atmosphere. However, the sign of the net global radiative effects of carbonaceous aerosols from the residential sector and solid-fuel cookstove emissions (warming or cooling) is not well constrained based on evidence from recent global atmospheric modelling studies. Estimates of direct aerosol – radiation and aerosol – cloud effects from the global residential sector range from –20 to +60 mW m <sup>–2</sup> ( [[#Kodros--2015|Kodros et al., 2015]] ) and –66 to +21 mW m <sup>–2</sup> ( [[#Butt--2016|Butt et al., 2016]] ) and from –20 to +10 mW m <sup>–2</sup> ( [[#Kodros--2015|Kodros et al., 2015]] ) and –52 to –16 mW m <sup>–2</sup> ( [[#Butt--2016|Butt et al., 2016]] ), respectively. Uncertainties are due to assumptions about the aerosol emissions masses, size distribution, aerosol optical properties and mixing states (Section 6.3.5.3). Allowing BC to act as an INP in a global model leads to a much larger global forcing estimate from –275 to +154 mW m <sup>–2</sup> with a large uncertainty range due to uncertainty in the plausible range of maximum freezing efficiency of BC (Huang et al. , 2018). The residential biofuel sector is a major concern for indoor air quality (Bonjour et al. , 2013). In addition, several atmospheric modelling studies find that this sector is also important for outdoor air quality and even a dominant source of population-weighted outdoor PM <sub>2.5</sub> in India and China ( [[#Lelieveld--2015b|Lelieveld et al. 2015b]] , Silva et al. , 2016; Spracklen et al. , 2018; Reddington et al. , 2019).

The net climate effect of a one-year pulse of current emissions from the residential sector is warming in the near term of +0.0018°C ± 0.00084°C from fossil fuel use and +0.0014°C ± 0.0012°C from biofuel use. Over a 100-year time horizon, this warming is +0.0017°C ± 0.00017°C and +0.0001°C ± 0.000079°C, respectively ( [[#Lund--2020|Lund et al., 2020]] ). This is due to the effects of BC, methane, CO and NMVOCs, which add to that of CO <sub>2</sub> , but the uncertainty in the sign of carbonaceous aerosol net effects challenges overall quantitative understanding of this sector and leads to ''low confidence'' in this assessment. Residential sector emissions are an important source of indoor and outdoor air pollution in Asia and globally ( ''high confidence'' ).

<div id="6.6.2.3" class="h3-container"></div>

<span id="transportation"></span>