COLLECT for free in AS LITTLE AS 60 SECS large item delivery from next day Look out for products badged Fast Track to get it today - Collect in as little as 60 seconds - 7 days to collect - Dedicated Fast Track counter in-store - 7 days a week - Buy before 6pm and we'll deliver by 10pm - Choice of 4 delivery slots From next day, 7 days a week Choice of 4 delivery slots >  Heating and cooling 1 - 46 of 46 items Air purifiers can freshen your home and help clean the air if you suffer from allergies, making it easier for you to relax rather than stress about your next asthma attack or allergic reaction. We have a variety of different models, so you can be sure to pick the one that suits your needs but also looks great in your home. If you find a build-up of mould on your walls or a smell of damp in your house then you may have a problem with excess moisture in the air - a dehumidifier can help deal with this and leave you and your house protected from damp to allow you to breath more freely.

You might be interested in browsing our floor cleaner section, where we have vacuum cleaners and other cleaning products that will help you to reduce dust levels in your home. It might also be time to think about swapping that old sofa for a newer model from our sofas section to keep build up to a minimum.biozone air purifier hk HEPA Spare Filter for Honeywell Air Purifier.sharp air purifier ig-a10k HoMedics Spare Filter for AR-20 HEPA Air Purifier.sharp air purifier kc-850u manual HoMedics Spare Filter for AR-10 HEPA Air Purifier. Heaven Fresh HF380A Air Purifier. Heaven Fresh HF310A Air Purifier. Heaven Fresh HF380 Air Purifier.[1] Among the volatile organic compounds emitted by vegetation, isoprene, monoterpenes, sesquiterpenes, and their derivatives are thought to contribute to secondary organic aerosol formation.

Although it is well known that microscopic fungi globally turn over vast amount of carbon by decomposing the organic matter in the soil, vegetation is considered as the exclusive source of biogenic secondary organic aerosol precursors in various atmospheric models. Secondary fungal metabolites including sesquiterpenes have been recognized as characteristic volatile organic compounds emitted by fungi. In the present study, we investigated the rates of sesquiterpene emission of microscopic fungi to establish their potential significance compared to those from vegetation. To sample the headspace of the pure culture of some common fungi, we used an aseptic flow-through apparatus designed for solid phase microextraction in our laboratory. The identified sesquiterpenes in the headspace extracts were quantified for eight strains of microscopic fungi belonging to four different genera. Our results showed that microscopic fungi emit a considerable amount of sesquiterpenes. Based on our first estimations microscopic fungi may be considered as potentially significant sesquiterpene emission sources whose contribution to secondary organic aerosol formation may be comparable to that of vegetation.

[2] An important fraction of volatile organic compounds (VOCs) emitted by vegetation participates in the formation and growth of secondary organic aerosol (SOA), thereby directly and indirectly affecting the Earth's radiation balance. Although gas and particulate phase atmospheric reactions and gas-to-particle partitioning have been studied extensively, important sources of SOA precursors remain poorly characterized. The biogenic organic precursors which are of relevance in SOA formation are primarily isoprene, monoterpenes, sesquiterpenes, and their derivatives. Recent modeling studies have suggested that isoprene photooxidation may produce 4.6 Tg SOA per year while 12.2 Tg SOA per year are formed by the oxidation of other biogenic VOCs (BVOCs) [Tsigaridis and Kanakidou, 2007]. Sesquiterpenes (SQTs) are considered to be important biogenic SOA precursors in the atmosphere among the several hundreds of volatile organic compounds emitted by vegetation [Griffin et al., 1999]. Some SQTs have been found to be extremely reactive in the atmosphere.

They react with ozone, OH, and NO3 radicals within minutes, and their SOA yields have been determined to be significantly higher than those of monoterpenes [Griffin et al., 1999]. Quantitative SQT emission rate and landscape flux estimates are scarce and highly uncertain due to their low volatility and high chemical reactivity [Ciccioli et al., 1999].[3] Despite the high uncertainties in BVOC emission measurements, global VOC inventories consider plant emissions as the exclusive source of SOA precursors [Guenther et al., 1995]. It is well known that microscopic fungi turn over a vast amount of carbon by decomposing organic litter and detritus globally, on the order of tens of PgC per year. Nevertheless, atmospheric VOC inventories do not yet include emission of secondary metabolites from soil fungal communities. These metabolites have received growing attention in food security monitoring due to the health hazard and economic consequence of mycotoxin production in food. Detection of fungal volatiles can be used for fingerprinting fungal infection in agricultural commodities, especially in grains, and in indoor environment since the emitted metabolites, such as saturated and unsaturated hydrocarbons, alcohols, ketones, esters, monoterpenes, sesquiterpenes, diterpenes, nitrogen, and sulfur compounds are characteristic of individual species [Kuske et al., 2005].

Secondary fungal metabolites have been identified to indicate the microbial infection in indoor air quality studies or to prevent the decrease of nutritional value of agricultural commodities [Moularat et al., 2008]. Sesquiterpene biosynthesis in fungi was found to be regulated by the isoprenoid biosynthetic gene sesquiterpene cyclase, which is dissimilar to those in plants, implying independent origin of the cyclase genes in the two kingdoms [Proctor and Horn, 1993]. Nevertheless, the mechanisms of the reactions were found to be essentially identical. The highest MVOC (microbial volatile organic compounds) production associated with secondary fungal metabolism (specifically terpenes and sesquiterpenes) was found to occur prior to and during sporulation and mycotoxin production [Zeringue et al., 1993]. In general, conditions favoring growth also favor the production of secondary volatile metabolites in fungi [Frisvad et al., 1998].[4] Globally, the most abundant fungal species belong to the Penicillium, Aspergillus, Trichoderma, and Mucor genera.

Members of these taxonomic groups are common in indoor mold; some of these widely known fungus genera are efficient plant pathogens and they produce toxins and may cause allergy related illnesses. These species have been isolated from a wide range of environmental samples, such as foodstuffs, soils, and cereals. Among their volatile metabolites representatives of several compound classes were identified [Börjesson et al., 1996; Fischer et al., 1999]. In spite of the fact that the compositions of MVOCs emitted by fungi strongly depend on environmental conditions, sesquiterpenes have been reported as typical metabolites of the most abundant fungal species [Fiedler et al., 2001]. Given the proven abundance of SOA precursors among the fungal metabolites and the important role that the same microscopic fungi play in the global biogeochemical cycling of carbon, it is reasonable to ask how their emissions compare with those of living plants in the global inventory of known SOA precursors. The aim of this study is to quantify the sesquiterpene emission from some abundant fungi in order to assess their potential contribution to SOA formation.